Plug-In Hybrid Electric Vehicles: How Does One Determine Their Potential for Reducing U.S. Oil Dependence?

Estimation of the potential of plug-in hybrid electric vehicles’ (PHEV’s) ability to reduce U.S. gasoline use is difficult and complex. Although techniques have been proposed to estimate the vehicle kilometers of travel (VKT) that can be electrified, these methods may be inadequate and/or inappropriate for early market introduction circumstances. Factors that must be considered with respect to the PHEV itself include (1) kWh battery storage capability; (2) kWh/km depletion rate of the vehicle (3) liters/km use of gasoline (4) average daily kilometers driven (5) annual share of trips exceeding the battery depletion distance (6) driving cycle(s) (7) charger location [i.e. on-board or off-board] (8) charging rate. Each of these factors is actually a variable, and many interact. Off the vehicle, considerations include (a) primary overnight charging spot [garage, carport, parking garage or lot, on street], (b) availability of primary and secondary charging locations [i.e. dwellings, workplaces, stores, etc] (c) time of day electric rates (d) seasonal electric rates (e) types of streets and highways typically traversed during most probable trips depleting battery charge [i.e. city, suburban, rural and high vs. low density]; (f) cumulative trips per day from charger origin (g) top speeds and peak acceleration rates required to make usual trips. Taking into account PHEV design trade-off possibilities (kW vs. kWh of battery, in particular), this paper attempts to extract useful information relating to these topics from the 2001 National Household Travel Survey (NHTS), and the 2005 American Housing Survey (AHS). Costs per kWh of PHEVs capable of charge depleting (CD) all-electric range (CDE, or AER) vs. those CD in “blended” mode (CDB) are examined. .Lifetime fuel savings of alternative PHEV operating/utilization strategies are compared to battery cost estimates.